title: A computer analysis method for correlating knee X-rays with continuous indicators.
abstract: OBJECTIVE
  To develop an image analysis method that can automatically find correlations between a set of plain radiographs and continuous clinical or physiological indicators.
  
  
  METHODS
  Knee X-rays taken from the Baltimore Longitudinal Study of Aging are used in this study. The computer analysis method is based on the WND-CHARM image feature set filtered by using the Pearson correlation of each feature with the continuous variable, and the estimated value is determined by a weighted nearest neighbor interpolation.
  
  
  RESULTS
  Experimental results using 300 radiographs show that the proposed method can correlate knee X-rays with physiological indicators such as sex, age, height, weight, and BMI. For instance, the Pearson correlation between the X-ray images and the height and weight were 0.59 and 0.62, respectively.
  
  
  CONCLUSIONS
  Using computer analysis, X-ray images can be correlated to continuous physiological variables that might not have a direct and straightforward link to the visual content of the radiograph. This approach of radiology image analysis can be used in population studies for detecting biomarkers and also in genome-wide association studies for studying the link between genes and anatomy.
authors.affiliation: Lawrence Technological University, 21000 W Ten Mile Rd., Southfield, MI 48075, USA. lshamir@mtu.edu
authors.forename: Lior
authors.initials: L
authors.lastname: Shamir
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D000465:Algorithms; D000886:Anthropometry; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D011859:Radiography / Q000379:methods*; D012680:Sensitivity and Specificity